Vehicles using combustion engines include a manufactured vessel (e.g., a blow molded fuel tank) to hold the fuel used to fuel engine combustion. Accurate fuel level readings enable a vehicle operator to better manage fuel refilling during vehicle operation.
In order to collect fuel level information, fuel tanks may use a float attached to an arm, where a fuel level measurement module can determine the volume of fuel remaining by the position of the arm and calibrated knowledge of the shape of the fuel tank. However, in cases where the fuel level measurement module is not in the calibrated position, or orientation, the arm position may not indicate the correct fuel level based on the shape knowledge of the fuel tank. Specifically, as taught in US Patent Application Publication No. US 2012/0234074 A1 titled “Measurement device and method for determining a fluid fill level in a fuel tank”; the tilting of components of the measurement device may cause incorrect fill level indications in conventional measurement devices.
Fuel tanks are dimensionally challenging to manufacture. The parralellism requirement for the internal tank bottom surface, underneath the fuel level measurement module, is an important characteristic in how the level sensing float is able to properly gauge the depth of the fuel in the tank—this is especially critical at very low fuel levels. The typical methods of controlling the parralellism of the internal bottom surface of the fuel tank, however, often fail to produce desirable results, potentially leading to unintended, or inaccurate, fuel level indication information being presented to the driver of the vehicle.
Rather than, or in addition to, trying to control the tank bottom surface as an aggregate surface, one example approach has a fuel tank with a bottom inner surface including a first region below a fuel tank insert, the bottom inner surface including a plurality of flat-topped support domes defining a common plane. The bottom surface may further include a second region below a float, the second region including at least one flat-topped support dome further defining the common plane. In this way, the tolerance of the bottom surface can generally be relaxed while maintaining the parralellism, of the domes to a tighter tolerance. Such an approach can reduce overall costs, speed manufacturing, while increasing fuel level measuring.
In one example, a number of discrete small support domes, or peaks, may be provided in the area(s) of interest and contact with other components. The support domes can be raised and lowered via simple tank mold modifications with precision to allow for “tuning in” of the relationship of the fuel reservoir to another feature or area of the tank. This approach frees the majority of the tank bottom surface from strict parralellism, requirements, allowing for improved and accurate fuel level information to be collected along with easier and improved tank manufacturing.
The inventors herein have recognized the issues noted above, as well as the various approaches herein to at least partially address them.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.